Appliance for closing a switch for parallel connection of two networks or a network with incoming generator



July 22, 1947. A. GANTENBEIN m AL 2,424,447

APPLIANCE FOR CLOSING A SWITCH FOR PARALLEL CONNECTION OF TWO NETWORKSOR A NETWORK WITH INCOMING GENERATOR Filed Feb. 2, 1945 iatented July22, 1947 PARALLEL CONNECTION OF TWO, NET- WORKS OR A NETWORK-WITHIINCOMING GENERATOR Andreas Gantenbein and .1656 Jackie; Zurich,

Switzerland,

assignors to: Mascliinenfabrik Oerlikon, Zurich-Oerlikon, SwitzerlandApplication February 2, 1945, SeriaTNo, 575,842 In Switzerland November19, 1943' 11 Claims. (01. 171-118) Thepresent invention relates to a newand improved" device for closing: a switch for the connecting inparallel of two alternating current networks-or of alternating currentnetworkwlth an incoming generator. Connection inparallel of alternatingcurrent'systems' with comparatively: greati-difierences' offrequencies'is only possiblewhen the time interval associated with theconnecting operation, namely the time constant of the switch is takeninto consideration by a certain angle of advance which corresponds tothe momentary diflerence in frequency between the two networks, uso thatclosing of the breaker contacts takes placeat zero phase displacement.The different appliances in-use up to the'present time have manydisadvantages, their construction is complicated: and they areunreliable in operation;

The object o-f-the inventionisto provide anew, simple and reliablearrangement of a' device which allows the actual closing of the breakercontacts-r of the' two networks to' takeplace at phase coincidence;

A further object" ofthe'invention: consists: in the provision of anappliance for parallel connection, in which theconnection takesplace'atthe correcttime when phasecoinciden'ce has-been established; wherebyat'the sarnetime', however; the difference in frequency'm'ay'varywithinpredetermined adjustable limits; Theinventionwillbe betterunderstood from the following descriptionrtaken in connection with theaccompanying drawings in" which a device for connecting" inparallel-twonetwork s is shown in adiagrammatical manner.

In the 'drawing-a-cont'actA is rotatably mounted'on the shaftof-a'syi'ich'ro-nos'cope the speed ofrotation of which is equal to the*difierence of frequencies between the two networks, it alsoindicates'the instantaneous relative phase position' of the incoming generator. Atthe same time a second contact-B, arranged I concentrically with A;moves at a spee'd that is directly proportional to the difference offrequencies between the'two networks. Whenn'ow contact A init-s travelslides over the contact B, electrical contact le established betweenthem; the operation of:closin'g'thebrealier switchstarts, with dueregard' to the timeeleinent and the angle of a'd-- vance'required dueto'the particular closing time constantof the breaker switch, the actualclosm 01' the breaker 'coritacts -occurringat zero phase 'displacem'ent;r k

The two networks I and'i canf-be connectedin arallellby-means of -th'ebleakerswitch3'. A

24 synchron'oscope"1 is connected with both networksthr'ough the twotransformers 5 and 6. A pointer arm 24" with a rolling contact A isrigidlyco'nnect'e d to" the rotatable shaft 28 of the synchronoscope 1.-The rolling contact A isin continuous engagement with the largercircumference of a stepped pulley 23 and is adapted to conductivelyen'gagea contact Bmounted at one point of thi's' circumference. Thestepped pulley 23' is freely rotatably mounted on the shaft 28 anditssr'n'aller diamete'rstep is engaged by an endless belt 22-pa'ss'ingalso over another stepped pulley l4 having one of itssteps engaged by abelt 30 the parallel ends of which are secured eachby a spring l5 toail-anchor bar Hi; The belt '30 and the springs l-5' yieldingly' resistrotation of the pu'lleys'M -and-23 'andtry to maintain andreturn thesame to a pb'sit'ion'in which the contact-B onthe pulley 23 is in" acertain rest position 0 as indicated by a pointer 25 secured to thepulley '23 and pla'ying over a scale on a stationar dial Z EI' The S oppd pulley M is fixedly m'oun'te'd o'n a rotatable control shaft 29 0f aneddy current coupling as will appear pres-' entlyp y m Thesha'ft ZBliasrigidIy secured thereto a gear 8--which meshes with a gear fixed'tothe rotor shaft 3 or an electi e-magnetic eddycur'rent slip coupling;This electromagnetic-slip coupling consists"essentially of arotorshaving solid poles anda' cylihdricalstator' I ll provided with anann'u'lar 'eXeiting 'ccil H'; The rotor 9 is driven by niean's ofithegears 8"and' 8dfrom the shaft 28' of tl'i'e'synchr'oiioscope l. The coil32'is energized" with" direet' current' by the lines I3 containing a;regulating resistance l2; An aluminum drum" l l which-is fixedly securedwith one of its-ends to the previouslyniention'ed rotatable controlshaft 29': extends freely'movable-into the air gap formed betweenthe'sta't'or bore and the rotor 9. The aluminum drum 1 l iservesas' aninductor in which are produced eddyrc'urrents'when the exciting coil 3-2is energized and the rotor 9 is rotated by the shaft 28 and'theg6als8and 8a. The eddy currents fora predetermined excitation areproportional to the number of revolutions of the r0- tor Q'and the-shaft28--respective1y, and. are also proportional to the counter torqueacting on the aluminum drum IL. and derived from the belt andspringassembly 30, I5 which, as mentioned previously, resists yieldingly anyrotative movem'ent'oi'the" stepped pulley l4 fixedly secured to theshaft29. v

The degree of angular displacement of the drum" l l andoftheconta'ct Bfrom its/normal zero position for a predetermined excitation of the coil32 is therefore a function of the speed or number of revolutions of theshaft 28 of the synchronoscope, or in other words, it is a function ofthe difference in frequency between the two networks.

A third step of the stepped. pulley I4 is provided with a contact sectorI! of a frequency limit control device. Two contact rollers l9 are incontinuous rolling contact with the circumference of the third step ofthe stepped pulley and in certain positions of the latter are both inconductive contact with the contact sector ll. The rollers 19 areadjustable along stationary conductor rails l8 arranged concentricallyabout the pulley l4 and are provided with pointers 20 indicating theadjusted position of the rollers IS on a stationary dial 2|. The contactB is conductively connected by a lead 35 with the relay 4 which whenenergized will actuate the breaker switch 3 and thereby the two networksI and 2 will be connected with each other in parallel. The contactroller A is conductively connected by the pointer arm 24, a Slidingcontact brush 35 and a conductor 31 with one of the two conductor rails18. The other conductor rail 18 is connected with the relay by aconductor 38.

From the above described circuit connections it is obvious, that therelay 4 can only be operated to close the breaker switch 3 When firstly,the contact roller A engages the contact 13, and secondly, when at thesame time the contact sector I! is engaged by both rollers H3.

The adjustable resistance I2 is employed for changing the excitation ofthe coil 32 so that the angle ofadvance can be adjusted to correspond tothe time constant of the breaker switch 3 so that the latter isautomatically closed at the very moment the phases of both networks Iand 2 are coincident with each other.

The mode of operation is as follows:

If the prevailing difference of frequencies between the two networks isgreater than that predetermined by the adjustment of the rollers l9along with their respective rails [8, the torque exerted by the drum IIwill be sufficiently great to cause the sector IT to rotate out ofengagement with one of the contact rollers [9. The relay controllingcircuit is interrupted and closing of the breaker contacts cannot takeplace. As soon as the frequency difference becomes smaller and comeswithin the predetermined permissible limits, both rollers I9 will engagethe sector i1. Connection can then be established to close the breakercontacts when contact B comes into contact with A during its rotarymotion.

The angular deviation of the pointer 25 on the pulley 23 from the zeroposition on the dial 26 indicates the momentarily prevailing frequencydifference. This deviation corresponds directly to the angle of advanceand the time factor. The angular deviation of the pointer 24 carryingthe contact A from the pointer 25, however, indicates the momentarilyprevailing difference in the phase position between the two networks.

This arrangement can be improved by duly taking into consideration themomentary difference of acceleration of frequency of the two nets. Thiscan be accomplished by adjusting the anchor bar l6 of the springs IS,the bar is moved horizontally either to the right or to the left,depending on the sign of the acceleration-difference.

The electric synchronoscope can also be replaced by two synchronousmotors and a mechanical differential gear.

What it is desired to secure by United States Letters Patent is:

1. In a device for closing an electric switch for connecting twoalternating current networks in parallel, a shaft rotating with a speedcorresponding to the difference in frequency between the two networks,an electric contact radially spaced from said shaft and carried by amember fixedly secured to said shaft, a second electric contact arrangedin the path of movement of the first mentioned contact, electric circuitmeans connected with said two contacts and adapted to cause saidelectric switch to close when said two contacts engage each other, andmeans for adjusting said second electric contact concentrical- 1y aboutthe axis of said shaft in accordance with the frequency differencebetween said two networks, said means being actuated by said shaft andincluding a control device arranged in said electric circuit means forpreventing the closing of said electric switch as long as the differencein frequency between the two networks exceeds a predetermined value.

2. In a device for closing an electric switch for connecting twoalternating current networks in parallel, a synchronoscope having ashaft rotating with a speed corresponding to the difference in frequencybetween the two networks, an electric contact radially spaced from saidshaft and carried by an arm fixedly secured to said shaft, a secondelectric contact arranged in the path of movement of the first mentionedcontact, electric circuit means connected with said two contacts andadapted to cause said electric switch to close when said two contactsengage each other, and means for adjusting said second electric contactconcentrically about the axis of said shaft in accordance with thefrequency difference between said two networks, said means beingactuated by said synchronoscope and including a control device arrangedin said electric circuit means for preventing the closing of saidelectric switch as long as the difference in frequency between the twonetworks exceeds a predetermined value.

3. In a device for closing an electric switch for connecting twoalternating current networks in parallel, a shaft rotating with a speedcorresponding to the difference in frequency between the two networks,an electric contact radially spaced from said shaft and carried by amember fixedly secured to said shaft, a second electric contact arrangedin the path of movement of the first mentioned contact, electric circuitmeans connected with said two contacts and adapted to cause saidelectric switch to close when said two contacts engage each other, meansfor adjusting said second electric contact concentrically about the axisof said shaft in accordance with the frequency difference between saidtwo networks, said means being actuated by said shaft and including acontrol device arranged in said electric circuit means for preventingthe closing of said electric switch as long as the difference infrequency between the two networks exceeds a predetermined value, andmeans associated with said second contact adjusting means for angularlyshifting said second contact away from a normal zero position inaddition to the angular adjustment effected by said shaft forconsidering the phase displacement due to the time constant of saidelectric switch and insuring a closing of said switch at phasecoincidence.

In a device for closing an electric switch for connecting twoalternating current networks in parallel, a shaft rotating with a speedcorrespondingto-the difference in frequency between the two networks, anelectric contact radially spaced from said shaft and carried by an armfixedly secured tosaid shaft; 3, second electric contact arranged inthepath of movement of the first mentioned, contact, electric circuitmeans connected with said two contacts and adapted to cause saidelectric-switchfto close when said two contacts engage: each other, andmeans for adjusting said second'electric contact concentrically aboutthe axis of said shaft in accordance with the frequency differencebetween said two networks, said means comprising an electromagnetic slipclutch provided with a pole shoe carrying rotor, a gear connectionbetween said shaft and said rotor, a stator provided with a variableexcitable field coil, a cylindrical metallic drum loosely rotatable inthe air gap between said rotor and said stator, means for transmittingthe rotative movement of said drum to said second electric contact, anda control device arranged in said electric circuit means for preventingthe closing of said electric switch as long as the difference infrequency between the two networks exceeds a predetermined value.

5. In a device for closing an electric switch for connecting twoalternating current networks in parallel, a shaft rotating with a speedcorresponding to the difference in frequency between the two networks,an electric contact radially spaced from said shaft and carried by amember fixedly secured to said shaft, a second electric contact arrangedin the path of movement of the first mentioned contact, electric circuitmeans connected with said two contacts and adapted to cause saidelectric switch to close when said two contacts engage each other, andmeans for adjusting said second electric contact concentrically aboutthe axis of said shaft in accordance with the frequency differencebetween said two networks, said means comprising an electromagnetic slipclutch provided with a pole shoe carrying rotor, a gear connectionbetween said shaft and said rotor, a stator provided with a variableexcitable field coil, a, cylindrical metallic drum loosely rotatable inthe air gap between said rotor and said stator, spring actuated meansfor resisting the rotative movement of said drum, means for transmittingthe rotative movement of said drum in excess of that compensated by saidspring actuated means to said second electric contact, and a controldevice arranged in said electric circuit means for preventing theclosing of said electric switch as long as the difference in frequencybetween the two networks exceeds a predetermined value.

6. A device as claimed in claim 4, including a pointer connected withsaid second contact and a stationary dial having a scale associated withsaid pointer to indicate the momentary difference in frequency betweenthe two networks.

7. A device as claimed in claim 4, including a pointer connected withsaid second contact, a

stationary dial having a scale associated with said pointer to indicatethe momentary difference in frequency between the two networks, andanother pointer connected with said contact carried by the arm on saidshaft, the angular distance between said two pointers indicating themomentary angular phase displacement between the two networks to beconnected in parallel.

8. A device as claimed in claim 5, including a control shaft on whichsaid drum is fixedly secured aimulti-step pulley. secure d:'-tosaidicon'trol shaft, another pulley onsaid first namedshaft whichrotates with aspeed corresponding to the difference in frequency betweenthe two networks, an endless beltconnecting the last named. pulleyWithone'step of themulti-step pulleyon the control shaft, abelt passingover another" stepof the-multi s'teppulley; thje ends of said beltfbeing arranged substantially parallel, and springs attachedtotheparallel'ends ofsaid' belt and toan anchor 'bar, v so as to retainthe belt jtensioned' and resisting-rotative movement. of saidpulleys-said contact device being operated by said control shaft whichcarries a contact element adapted to engage two contacts and close saidelectric circuit means when the difference in frequency between the twonetworks is within predetermined limits.

9. A device as claimed in claim 5, includin a control shaft on whichsaid drum is fixedly secured, a multi-step pulley secured to saidcontrol shaft, another pulley on said first named shaft which rotateswith a speed corresponding to the difference in frequency between thetwo networks, an endless belt connecting the last named pulley with onestep of the multi-step pulley on the control shaft, a belt passing overanother step of the multi-step pulley, the ends of said belt beingarranged substantially parallel, and springs attached to the parallelends of said belt and to an anchor bar, so as to retain the belttensioned and resisting rotative movement of said pulleys, said contactdevice comprising a contact sector fixedly attached concentrically onsaid rotatable control shaft, two stationary contact rails arrangedconcentrically with respect to said contact sector and carrying each anadjustable contact member adapted to engage said contact sector, theadjustment of said contact members along their respective contact railsdetermining the limits of the difference in frequency between the twonetworks within which the electric switch is actuated when both saidcontact members are engaged by said contact sector.

10. A device as claimed in claim 5, including a control shaft on whichsaid drum is fixedly secured, a multi-step pulley secured to saidcontrol shaft, another pulley on said first named shaft which rotateswith a speed corresponding to the diiference in frequency between thetwo networks, an endless belt connecting the last named pulley with onestep of the multi-step pulley on the control shaft, a belt passing overanother step of the multi-step pulley, the ends of said belt beingarranged substantially parallel, and springs attached with one end tothe parallel ends of said belt and with their other ends to an anchorbar, so as to retain the belt tensioned and resisting rotative movementof said pulleys, said contact device comprising a contact sector fixedlyattached to the circumference of another step of said multi-step pulley,two stationary contact rails arranged concentrically with respect tosaid contact sector and carrying each an adjustable contact memberadapted to engage said con-tact sector, the adjustment of said contactmembers along their respective contact rails determining the limits ofthe difference in frequency between the two networks within which theelectric switch is actuated when both said contact members are engagedby said contact sector, and a pointer on each said contact members andcooperating with a scale on a fixed dial for indicating the adjustmentof said contact members.

11. A device as claimed in claim 5, including a control shaft on whichsaid drum is fixedly secured, a multi-step pulley secured to saidcontrol shaft, another pulley on said first named shaft which rotateswith a speed corresponding to the difierence in frequency between thetwo networks, an endless belt connecting the last named pulley with onestep of said multi-step pulley on the control shaft, a belt passing overanother step of the multi-step pulley, the ends of said belt beingarranged substantially parallel, and springs attached to the parallelends of said belt and to an anchor bar, so as to retain the belttensioned and resisting rotative movement 0! said pulleys, said anchorbar being adjustable in a plane parallel to a plane in which saidcontrol shaft is arranged to vary the angular zone of the pulley engagedby said belt, said contact device being operated by said control shaftwhich carries a contact element adapted to engage two contacts and closesaid electric circuit means when the difference in frequency between thetwo 10 networks is within predetermined limits.

ANDREQS GAN'IENBEIN. JosE' JACKLE.

